DESCRIPTION: (adapted from applicant's description) A prospective cohort study is proposed to assess the effects of lead exposure on endocrine dysfunction and adverse reproductive outcomes in China. The investigators will enroll a total of 800 women (400 lead-exposed and 400 unexposed), in Shenyang, China, who are married and between 20 and 34 years of age, who are never smokers, who have obtained permission to have a child, and who will be attempting to become pregnant over the course of the study. Lead exposure will be defined by lead levels in blood samples collected at the baseline survey (both women and their husbands), first and second trimesters, and at delivery (both maternal and cord blood). Endocrine dysfunction will be monitored by urinary hormone metabolites, including follicle-stimulating hormone (FSH), leutinizing hormone (LH), estrone conjugates (E1C), and pregnanediol-3-glucuronide (PdG). Reproductive endpoints will include menstrual disturbance, time to conception, spontaneous abortion, preterm delivery, and low birth weight. After enrollment, interviewers will administer a questionnaire to the women and their husbands to collect baseline information on reproductive history, sociodemographic, environmental, and personal covariates. Height and weight will be measured by standard methods. A follow-up study and a nutritional survey will be conducted trimonthly. Each woman will keep a diary of her menstrual period and related symptoms, sexual activity, general health status, medication, contraceptive use, active and passive smoking, indoor air pollution, alcohol use, amount of vigorous exercise and physical activity, emotional upset, and changes in job activity and lifestyle. Daily urine samples will be collected from each subject for up to one year or until pregnancy occurs. Urinary Beta-hCG will be measured to identify subclinical pregnancy. Once a woman becomes pregnant, she will be followed for pregnancy outcomes.